Permeability tuning slug support



Nov. 15, 1949 R. c. CARLSON 2,488,375

PERMEABILITY TUNING SLUG SUPPORT Filed March 28, 1945 r .1. INVENT OR.

FH/BEN C. CARL SON fi -'4 ATTORNEY Patented Nov. 15, 1949 UNITED STATESPATENT PERMEABILITY TUNING SLUG surron'r Reuben C. Carlson, Chicago,Ill., aulgnor to Admiral Corporation, of Delaware Chicago, lll., acorporation Application March 28, 1945, Serial N0. 585,357

1 Claim.

This invention relates to tuning controls such as are used in connectionwith permeability tuned receivers and more particularly to an apparatusfor providing a more perfect alignment of the tuning elements for areceiver.

Although the invention about to be described will be described inconnection with permeability tuning controls for radio receivers, itwill be apparent that the invention is also useful in connection withcertain types of controls other than those used in permeability tuning.

As is well known to these well versed in the art, it is desirable, inconnection with radio' circuits, to provide an apparatus whereby certainof the circuits may be tuned to difierent frequencies. In some types ofreceivers, this is effected by varying the capacity and in others byvarying the inductance. Varying the inductance is commonly effected bymoving a core or slug composed of finely divided iron into properrelation with the inductance winding. Usually this is done by sliding acylindrical slug into the form which carries the winding. This presentsa problem during production, because the slug must fit closely in thecoil form so that it cannot move accidentally and cause the tuning tochange. The slug must still slide freely into the coil form andtherefore the alignment of the slug with the form has to be carefullycontrolled otherwise it will not slide in,

and out with case.

In commercial production this is somewhat difficult, making it necessaryto have precision controls and increasing the cost of the receiver. Thisproblem becomes more acute as the number of slugs to be moved isincreased, as in the case of a superheterodyne or multiband receiverwhere a number of circuits are tuned simultaneously.

By the present invention I am enabled to provide a slug supporting meanswhich allows the slug to readily align itself with the coil form. Byutilizing my improved slug support, I am able to increase the productionof tuners and eliminate the necessity of precision controls. Theimproved supports also permits rough and course adjustments to readilybe made during the construction of the receiver.

Other advantages of the invention and the invention itself will becomemore apparent from the following description of an embodiment thereof,which description is illustrated by the accompanying drawings and formsa part of this specification.

In the drawings:

Fig, 1 is a side elevational view of a tuning con trol assemblyembodying my invention;

Fig. 2 is a vertical sectional view taken on the line 2-2 of Fig. 1;

Fig. 3 is an enlarged fragmentary vertical section through one of theslug supports and showing a fragment of a slug in elevation;

Fig. 4 is a fragmentary plan view thereof;

Fig. 5 is a view similar to Fig. 3 of a modified form of the invention;

Fig. 6 is a fragmentary plan view thereof; and

Fig. 7 is a fragmentary perspective of the end of a wrench for adjustingthe device of Fig. 5.

In carrying out my invention, I preferably provide a connector which maybe adjustably connected to a control member and which carries flexiblemeans that in turn carries a tuning member; the flexible means permitsmovement of the flexible member and it in turn permits lateral movementof the tuning member allowing it to automatically align itself with themeans being tuned.

Referring now to the drawings throughout which like parts have beendesignated by like reference characters and particularly to Figs. 1 and2, I have illustrated a tuning sub-assembly which may be built upseparately from the re-' ceiver chassis and be attached thereto in anysuitable manner.

The assembly includes a support for the coils and their forms, acarriage for supporting the tuning slugs and a control means for movingthe carriage.

As is shown in the drawings, the tuning assembly includes a frame orchassis of open sided construction comprising sheet metal side walls I,2 and 3 and a bottom wall I. The coil forms 5 are carried by the bottomwall 4 being supported thereon in any desired manner and carry thereoninductance windings as indicated at 6.

The wall i is provided with an angularly disposed bracket 1 whichextends at right angles to the wall and is provided with a tongue 8extending parallel to the wall I. A shaftv 9 is journalled through thewall I and the tongue 8, and carries thereon a sheave it. The shaft maybe locked against removal from the tongue by a split ring H seated in agroove in the end of the shaft. The bracket 1 is also provided with waysi2 that slidably support a slide i3 which is-.-of L-shaped formation andcarries on its end a plate It. A cable i5 is secured at I6 to the slidebeing trained around the sheave l0 and has the other end secured by aspring I! to a lug l8 on the other end of the slide. When the shaft 9 isrotated the slide i3 is slid carrying with it the plate It.

The plate [4 is adapted to carry and control the positioin of aplurality of slugs which, when the plate I is moved, project into or arewithdrawn from the coil forms. As previously mentioned, there may be anydesired number of these forms. In the particular illustration there isshown four such forms and they are disposed in spaced parallel relationto each other.

The plate H is provided with a plurality of threaded apertures 2|, Fig.3, in which are screw 0 threaded bushings such as shown in Fig. 3. Eachbushing comprises an exterlorly threaded cylinuses" der 22 having a bore23 extending most of the way through the cylinder, and provided with anannular flange 24 on one end, and a flattened portion 25 on the otherend. The slug, illustrated at 26, as previously stated, comprises a coreof iinely divided iron and has secured therein during the manufacturethereof a wire or rod like member 21 which is imbedded in the slug asindicated by the dotted line 28. The member 21 has a certain amount offlexibility and extends through the bore 23 of the cylinder and throughthe opening in the end 25. It may project beyond the end as indicated at29.

In installing the device it is common practice to first roughly alignthe circuits by sliding the slug 26 in and out of the coil form, thewire 21 sliding in-the opening 25. Preferably the bushing 22 ispositioned by threading it through the plate ll for such a distance asto permit subsequent maximum adjustment thereof in either direction. Thesupport wire 21 is then slid in the bushing, and the slug in the coilform to provide a rough adjustment. The wire 21 may be then soldered onthe end at 29, or the material of the bushing may be upset or crimped tohold the slug permanently therein. After the rough adjustment is made,it is then possible to more accurately align the circuits by adjustingthe slug to its proper position relative to inductance by engaging theflattened end 25 with a suitable wrench or tool and screwing the bushing22 in or out of the opening 2|.

Inasmuch as the means for holding the coil forms sometimes does not holdthem exactly vertical or parallel to each other and also because theremay be slight discrepancies in the position of the slug bushings 21 inthe plate I4, considerable difficulty was sometimes had securingsufficiently accurate alignment of the slugs with the coil forms.

It will be noted that the support rod or wire 21 extends through thesleeve 23 and is secured at the end of the sleeve remote from the slugand that there is ample room between the rod and the interior of thesleeve in which space the rod may move. Since the rod is flexible, it isthus possible for the slugs to tilt in entering the coil forms or to betilted by the coil forms and thus allow the coil forms to automaticallyalign the slugs therewith. This could not readily be done if theconnection were a rigid connection. Also by this structure the rod 21has an effective length considerably greater than it should have if itwas connected at the end 24 of the member 22. This permits for greaterflexibility of the device and allows a compact assembly to be made whichdoes not take up a great amount of room in the receiver.

It will be seen therefore that the structure lends itself topreadjustments during the building of the receiver and to fineadjustments after the receiver is built and when the final alignment ofthe components are being made. Furthermore, with this structurestampings may be used for the control and a considerably cheaper type ofconstruction may be realized. The necessity for precision controls isthus eliminated and the operation of the device is made effectivethrough the utilization of my invention. It will also be seen that thestructure is cheap, easy to install and simple to manufacture.

In Fig. 5, I have shown a slight modification which has certainadvantages resulting in ease of operation and economies of manufacture.The upper end of the bushing, instead of being flattened as shown at 25in Fig. 3, is plain. This eliminates the operation of providing theflattened end. The slug rod or wire 21, in this instance, extendsthrough the end of the bushing, and after being roughly adjusted. aspreviously described, is bent over at 21', with the bent over portionlying flat against the end of the bushing. The end preferably extendsbeyond the side of the bushing.

After being bent over, the wire may be soldered to the end of thebushing. Because there is a greater area which may be soldered, itprovides a more secure connection for the wire, and the end whichextends beyond the side of the bushing provides a convenient means forsubsequent adjustment.

For adjusting the bushing a wrench formed as best shown in Fig. 7 may beprovided. This wrench comprises simply a cylindrical body 20, the insidediameter of which is sufliciently large to allow it to be slipped overthe bushing, and provided with diametrically opposed slots 2| either ofwhich may slip over the wire 21'. This wrench may have one or moreslots, only one at a time, however, having its walls in engagement withthe wire 21'.

It will be seen, therefore, that this structure lends itself to acheaper and yet more effective construction.

Having thus described my invention in an embodiment thereof, I am awarethat numerous and extensive departures may be made therefrom withoutdeparting from the spirit or scope of the appended claim.

I claim:

In a permeability tuner having tuning slugs and a movable frame, meansfor adjusting said slugs and connecting them to said frame comprising asemi-flexible wire extending from said slug, an adjustable member inthreaded engagement with said frame, and formed with an axiallyextending bore closed by an end wall remote from the slug, said wireextending into the bore in said adjustable member in spaced relation tothe wall of the bore, and adapted to extend through said end wall, andmovable longitudinally thereon for coarse adjustment and arranged to befixed in said end wall to provide final adjustment by rotating themember in the threads, said wile having an end portion extendingexteriorly beyond said end wall and bent laterally and adapted to befixedly secured to the end of said adjustable member, said bent portionbeing provided with a point, extending beyond the side of the adjustablemember, adapted for engagement with a wrench.

REUBEN C. CARLSON.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number

